package leetcode51_60;

import java.util.concurrent.ForkJoinPool;

/**
 * @author shhjiang_001
 * @create 2020-06-19 22:56
 */
        /*
        给定一个正整数 n，生成一个包含 1 到 n2 所有元素，且元素按顺时针顺序螺旋排列的正方形矩阵。
        示例:
        输入: 3
        输出:
        [
        [ 1, 2, 3 ],
        [ 8, 9, 4 ],
        [ 7, 6, 5 ]
        ]
        */

public class Solution59 {
    public int[][] generateMatrix(int n) {
        int l = 0, r = n - 1, t = 0, b = n - 1;
        int[][] mat = new int[n][n];
        int num = 1, tar = n * n;
        while(num <= tar){
            for(int i = l; i <= r; i++) mat[t][i] = num++; // left to right.
            t++;
            for(int i = t; i <= b; i++) mat[i][r] = num++; // top to bottom.
            r--;
            for(int i = r; i >= l; i--) mat[b][i] = num++; // right to left.
            b--;
            for(int i = b; i >= t; i--) mat[i][l] = num++; // bottom to top.
            l++;
        }
        return mat;
    }
}
